U.S. patent number 4,683,983 [Application Number 06/915,706] was granted by the patent office on 1987-08-04 for ladder leveling apparatus.
This patent grant is currently assigned to Gerald G. Baker. Invention is credited to Chester M. Murphy.
United States Patent |
4,683,983 |
Murphy |
August 4, 1987 |
Ladder leveling apparatus
Abstract
Ladder leveling apparatus includes a frame portion, a support
portion, a slider portion, a retainer portion and a positioner
portion. The frame portion includes an elongated U-shaped section,
the U-shaped section including a main section having a width
slightly larger than the width of a ladder leg. The main section
includes at least one longitudinal channel. The support portion
includes a foot member pivotally connected to the ladder leg. The
foot member includes a connector section and a base section. The
slider portion includes a guide member disposed within the channel,
the guide member having a width slightly less than the width of the
channel and a thickness slightly greater than the thickness of the
main section. At least one opening extends through the guide
member. The retainer portion includes a plate member disposed over
the guide member, the plate member having a width significantly
larger than that of the channel. An opening through the plate
member is aligned with the guide opening. A bolt member extends
through the plate and guide openings and extends beyond the main
section a distance sufficient to pass through an opening through
the thickness of the ladder leg. An adjustable fastener is disposed
on the free end of the bolt member securing the ladder leg to the
guide and plate members. The positioner portion includes a
transverse pin member extending through aligned openings in the
side sections.
Inventors: |
Murphy; Chester M. (Missoula,
MT) |
Assignee: |
Baker; Gerald G. (Missoula,
MT)
|
Family
ID: |
25436148 |
Appl.
No.: |
06/915,706 |
Filed: |
October 6, 1986 |
Current U.S.
Class: |
182/204;
182/111 |
Current CPC
Class: |
E06C
7/44 (20130101) |
Current International
Class: |
E06C
7/00 (20060101); E06C 7/44 (20060101); E06C
007/44 () |
Field of
Search: |
;182/201-205,184,224,108-110 ;248/188.2,188.8 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Machado; Reinaldo P.
Attorney, Agent or Firm: Urban; Arthur L.
Claims
What is claimed is:
1. Ladder leveling apparatus including a frame portion, a support
portion, a slider portion, a retainer portion and a positioner
portion; said frame portion including an elongated U-shaped
section, said U-shaped section including a main section having a
width slightly larger than the width of a ladder leg, transverse
side sections extending from said main section adjacent side edges
thereof along substantially the entire length of said main section,
said side sections having a width at least about equal to the
thickness of said ladder leg, said main section including at least
one longitudinal channel; said support portion including a foot
member extending from one end of said frame portion, said foot
member being pivotally connected to said ladder leg, said foot
member including a connector section and a base section disposed on
a free end of said connector section remote from said ladder leg;
said slider portion including a guide member disposed within said
channel, said guide member having a width slightly less than the
width of said channel and a thickness slightly greater than the
thickness of said main section, at least one opening through said
guide member; said retainer portion including a plate member
disposed over said guide member, said plate member having a width
significantly larger than that of said channel, an opening through
said plate member aligned with said guide opening, a bolt member
extending through said plae and guide openings and extending beyond
said main section a distance sufficient to pass through an opening
through the thickness of said ladder leg, adjustable fastening
means disposed on the free end of said bolt member securing said
ladder leg to said guide and plate members; said positioner portion
including a transverse pin member extending through aligned
openings in said side sections; whereby said apparatus can be
connected to a ladder leg with said bolt member and said fastening
mens tightened thereon, said apparatus slid along said ladder leg
to a desired position, and said pin member inserted through said
side sections to provide a safe extension of said ladder leg.
2. Ladder leveling apparatus according to claim 1 wherein said main
section and said side sections of said frame portion are formed as
a unitary structure.
3. Ladder leveling apparatus according to claim 1 wherein said
frame portion has a length at least twice the width thereof.
4. Ladder leveling apparatus according to claim 1 wherein said
channel extends along a major part of the length of said frame
portion.
5. Ladder leveling apparatus according to claim 1 wherein said main
section includes a plurality of spaced channels and said retainer
portion includes a plurality of bolt members therethrough.
6. Ladders leveling apparatus according to claim 1 wherein said
transverse side sections include a plurality of aligned openings
along the lengths thereof.
7. Ladder leveling apparatus according to claim 1 wherein said base
section of said foot member includes gripping means.
8. Ladder leveling apparatus according to claim 1 wherein said
guide member has a length more than twice the width thereof.
9. Ladder leveling apparatus according to claim 8 wherein said
guide member includes more than one opening along the length
thereof.
10. Ladder leveling apparatus according to claim 5 wherein said
plate member has a width spanning more than one channel with at
least one opening aligned with each channel.
11. Ladder leveling apparatus according to claim 10 wherein said
plate member has a generally quadrangular configuration with more
than one opening aligned with each channel.
12. Ladder leveling apparatus according to claim 1 wherein said pin
member includes retaining means holding the position thereof
between said side frame sections.
13. Ladder leveling apparatus according to claim 1 wherein said
ladder leg includes a horizontal passage from one side edge thereof
to the other carrying said pin member between said side frame
sections.
14. Ladder leveling apparatus according to claim 1 including
elongated flexible means connecting a head end of said pin member
with said frame portion.
Description
This invention relates to a novel apparatus for use with a ladder
and more particularly relates to a new apparatus for leveling a
ladder.
Ladders have been used throughout history. Originally, ladders were
made by tying spaced cross pieces between two long poles. The
spacing and parallelism of the cross pieces or rungs depended upon
the eye and skill of the workman. As civilization developed,
ladders were manufactured in shops and factories. Jigs and
templates were employed to insure the accurate and uniform
placement of the rungs. Ladders originally were constructed of
wood, but more recently aluminum ladders have become popular.
Ladders today are of two general types, step ladders and extension
ladders. Step ladders which ordinarily fold have an A-shaped
configuration with one side having a series of steps. Extension
ladders have two straight sections that are mounted in parallel
adjacent planes in an overlapping relationship. The sections can be
compressed for carrying and storage and extended to a desired
length for use. Although the two sections usually are used together
to provide a greater overall length than either section, they can
be separated and used individually if desired.
While step ladders are self supporting, extension ladders have to
be placed against a vertical surface such as a wall of a building.
The upper end of the ladder is placed in contact with the building
and the bottom end or legs of the ladder rest on the ground a
distance out from the building.
Extension ladders enable a person to reach a long distance above
the ground with a structure that is relatively compact, but such
ladders do have certain shortcomings. They are difficult to handle
and position when extended. Also, they have a very small horizontal
dimension compared with their extended length. This makes them very
unstable, and as a result, many injuries are incurred each year due
to persons falling from extension ladders.
Some falls are the result of persons reaching two far to the side
of the ladder so the center of gravity shifts away from the ladder
causing it to tip over. While tipping can occur when a ladder is
placed on a firm level base, the change of tipping is much greater
when the ladder legs are placed on a base that slopes to the left
or right. Since a ladder is very long as compared with its width,
any variation in the base surface on which the ladder rests is
magnified in the inclination of the ladder to the left or right of
its base.
To maintain a ladder vertical under such conditions, a workman
ordinarily will place an object under the bottom of the legs.
Usually, a rock or wooden board is placed under the leg. While this
may level the ladder at that particular position, moving the ladder
to another location, e.g. along a wall, may change the inclination
of the base surface requiring that a number of objects of different
thicknesses be available to provide the needed leveling. This can
make the leveling time-consuming and frustrating as well as of
questionable safety.
In situations in which the slope is quite pronounced or involves a
step, the use of thin spacers will not be sufficient. Using thicker
spacers may present the additional problem of keeping the spacer in
place and not shifting down the slope. Any movement of the spacer
can be disastrous and result in series injury.
To overcome these problems, a number of ladder leveling devices
have been proposed and patented. Examples of such include U.S. Pat.
Nos. 432,263; 809,057; 1,013,515; 1,179,391; 1,705,000; 2,115,395;
2,360,640; 2,599,117; 3,414,082 and U.S. Pat. No. Des. 230,370.
None of these devices have gained acceptance over the years. Some
are difficult to adjust. Others are not rigid enough for safe use.
Some are too expensive and still others are not adaptable to
different ladders.
Although injuries have been sustained through the years and were
tolerated, in recent years the very high cost of liability both in
claims and insurance as well as medical expenses have created a
crisis both for ladder manufacturers and also for users.
From the above discussion, it is clear that previous methods and
devices for leveling ladders have not proved satisfactory for many
users. Thus, there is a need for a new ladder leveling apparatus
that overcomes the shortcomings of earlier designs.
The present invention provides a novel ladder leveling apparatus
which not only overcomes the deficiencies of earlier devices but
also has features and advantages not found in such devices. The
ladder leveling apparatus of the present invention provides a high
degree of safety for the user. Also, the ladder leveling apparatus
can be adjusted easily and quickly to conform with different base
surfaces.
The ladder leveling apparatus of the present invention is simple in
design and can be produced relatively inexpensively. Commercially
available materials and components can be used in the fabrication
thereof. Conventional manufacturing techniques and procedures can
be utilized by semi-skilled labor in the production of the
apparatus.
The ladder leveling apparatus of the invention is durable in
construction and has a long useful life. Little, if any,
maintenance is required to keep the apparatus in good working
condition.
The apparatus can be mounted on a ladder leg easily and quickly
without special skills or tools. Only a minimum of instruction is
required to mount and use the apparatus efficiently.
The ladder leveling apparatus can be mounted on a variety of
ladders conveniently. The apparatus is adjustable to accommodate
wide variations in base surfaces. The apparatus can be modified
easily to meet special use conditions.
These and other benefits and advantages of the novel ladder
leveling apparatus of the present invention will be apparent from
the following description and the accompanying drawings in
which:
FIG. 1 is a view in perspective of one form of ladder leveling
apparatus of the invention in use with a ladder;
FIG. 2 is an enlarged front view of the ladder leveling apparatus
shown in FIG. 1;
FIG. 3 is a fragmentary view of the reverse side of the ladder
leveling apparatus shown in FIG. 2;
FIG. 4 is a fragmentary view of the ladder leveling apparatus shown
in FIG. 3 with the positioner portion below the ladder leg;
FIG. 5 is a fragmentary front view of the ladder leveling apparatus
shown in FIG. 2 with the plate section removed;
FIG. 6 is a sectional view of the ladder leveling apparatus shown
in FIG. 2 taken along line 6--6 thereof; and
FIG. 7 is a sectional view of the ladder leveling apparatus shown
in FIG. 2 taken along line 7--7 thereof.
As shown in the drawings, one form of the ladder leveling apparatus
11 of the present invention is mounted on a ladder 12. The ladder
12 includes legs 13 and 14. The bottom of ladder leg 13 rests on a
step 15. The other ladder leg 14 which is too short to contact the
ground 17 includes the ladder leveling apparatus to extend the
length of the leg so the ladder 12 will be stable and can be
climbed safely as shown.
The ladder leveling apparatus 11 of the invention includes a frame
portion 20, a support portion 21, a slider portion 22, a retainer
portion 23 and a positioner portion 24.
The frame portion 20 of the ladder leveling apparatus 11 includes
an elongated U-shaped section 26. The U-shaped section 26 includes
a main section 27 that has a width slightly larger than the width
of ladder leg 14.
Transverse sections 28 and 29 extend from the main section adjacent
side edges 30 and 31 thereof. The side sections 28 and 29 extend
along substantially the entire length of the main section. The side
sections have a width at least about equal to the thickness of the
ladder leg.
The main section 27 and the side sections 28 and 29 advantageously
are formed as a unitary structure. The frame portion 29 preferably
has a length at least twice the width thereof. The transverse side
sections 28 and 29 advantageously include a plurality of aligned
openings 35 and 36 along the lengths thereof.
The main section 27 includes at least one longitudinal channel 33
and advantageously a plurality of channels shown in the drawings as
channels 33 and 34. Preferably, the channel or channels extend
along a major part of the length of the frame portion.
The support portion 21 of the ladder leveling apparatus 11 of the
present invention includes a foot member 40. The foot member
extends from one end (the lower end) of the frame portion 20. The
foot member 40 is pivotally joined to the ladder leg 14 through a
connector section 41.
The foot member 40 also includes a base section 42. The base
section 42 is disposed on a free end of the connector section 41
that is remote from the ladder leg. The base section preferably
includes gripping means 43.
The slider portion 22 of the ladder leveling apparatus 11 includes
a guide member 45. The guide member 45 is disposed within channel
33. The guide member has a width slightly less than the width of
the channel to slide freely therealong. The guide member 45 has a
thickness slightly greater than the thickness of the main section
27.
The slider portion also includes at least one opening 46 through
the guide member 45. Advantageously, the guide member includes more
than one opening along the length thereof shown as openings 46 and
47. The guide member 45 preferably has a length more than twice the
width thereof.
The retainer portion 23 of the ladder leveling apparatus 11
includes a plate member 50. The plate member is disposed over the
guide member 45. The plate member 50 has a width significantly
larger than the width of the channel 33. The plate member includes
an opening 51 therethrough. The opening 51 is aligned with the
guide member opening 46.
A bolt member 52 extends through the plate opening 51 and the guide
opening 46. The bolt 52 further extends beyond the main section 27
a distance sufficient to pass through an opening 53 across the
thickness of the ladder leg 14 and beyond.
Adjustable fastener means 54 shown as nut 55 is disposed on the
free end 57 of bolt member 52, advantageously with a lock washer
58. Tightening the nut 55 on the bolt member secures the plate
section 50, the main section 27 and the ladder leg 14 together.
The plate member 50 advantageously has a width spanning more than
one channel shown as two channels 33 and 34 and has at least one
and preferably two openings aligned with each channel. Thus, in
addition to opening 51, the plate member includes openings 60, 61
and 62 which are aligned with openings 47, 64 and 65 respectively
in first and second guide members 45 and 66 for entry of bolts 67,
68 and 69. Plate member 50 advantageously has a generally
rectangular configuration although other shapes such as large
washers, pairs of elongated plates and other geometric shaped
plates may be employed.
The positioning portion 24 of the ladder leveling apparatus 11 of
the invention includes a transverse pin member 70. The pin member
70 extends through aligned openings 35 and 36 in the side sections
28 and 29 of the frame portion 20. Advantageously, the pin member
70 includes retaining means shown as depressable ball 71 adjacent
the free end of the pin member to hold the pin between the side
frame sections.
The pin member 70 also includes elongated flexible means shown as
chain 72. The chain 72 connects the head end 73 of the pin member
with the frame portion 20 to prevent loss thereof when not disposed
between the side sections.
The pin member preferably is inserted through a horizontal passage
75 that extends from one side edge 76 to the other 77 of the ladder
leg 15. This arrangement further secures the ladder leg to the
leveling apparatus 11. Alternatively, the pin member may be
disposed below the bottom 78 of the ladder leg as shown in FIG. 4
when speed of adjustment is critical.
The ladder leveling apparatus of the invention may be fabricated
from a variety of materials including metals, structural plastics,
combinations thereof and the like. The materials of particular
components are selected to provide high structural strength and
rigidity at lowest cost.
In the use of the ladder leveling apparatus 11 of the present
invention, the apparatus first is mounted on a ladder leg 14. This
is accomplished by positioning the frame portion 20 over the ladder
leg with the main section 27 against a major surface of the ladder
leg and the side sections 28 and 29 along the side edges 76 and 77
of the ladder. Next, a number of openings 53 are drilled through
the thickness of the ladder from one major face to the other. These
openings 53 are aligned with the bolt members 52, 67, 68 and 69.
Also, passage 75 is drilled transversely through the ladder
leg.
With the nuts 55 and washers 58 removed, bolts which already extend
through the plate section 50 and the guide members 45 and 66 are
threaded through the openings 53 in the ladder. Nuts 55 and washers
58 are replaced on the ends 57 of the bolts and tightened. This
secures the leveling apparatus 11 to the ladder leg 14 while
permitting the position of the apparatus to be adjusted with repect
to the ladder leg.
The frame portion 20 then is slid along the ladder leg to a
position that provides the desired extension of the leg. To fix the
position of the frame portion, passage 75 through the ladder leg is
aligned with corresponding openings 35 and 36 in the side sections
28 and 29. Pin member 70 is inserted through the aligned openings
and passage until it extends completely therethrough and ball 71
retains the pin therein. The ladder and leveling apparatus now are
ready for use.
The ladder 12 is positioned against a vertical surface such as a
wall of a building (not shown) with the bottom of ladder leg 13 in
contact with the higher base surface shown as step 15 and the other
leg 14 with the leveling apparatus in contact with the lower base
surface (ground 17). If the ladder is not precisely perpendicular,
the position of the apparatus 11 can be adjusted on the ladder leg
by releasing downward pressure and pulling pin 70 from the
apparatus. The position of the ladder is corrected and the pin
replaced through another pair of openings 35 and 36 that are
aligned with the ladder passage 75. This same adjustment is made
when the ladder is moved to a new location.
The above description and the accompanying drawings show that the
present invention provides a novel ladder leveling apparatus which
not only overcomes the shortcomings of earlier methods and devices
but in addition provides features and advantages not found in such
devices. The ladder leveling apparatus of the invention provides a
high degree of safety for the user. Also, the ladder leveling
apparatus enables a user to quickly and easily adjust the ladder
legs to accommodate varying base surfaces.
The ladder leveling apparatus of the invention is simple in design
and can be produced relatively inexpensively from commercially
available materials and components using semi-skilled labor and
conventional fabricating procedures. The apparatus is durable in
construction and has a long useful life with little
maintenance.
The leveling apparatus can be mounted on a ladder easily and
quickly without special tools or skills. The apparatus can be used
efficiently after a minumum of instruction even by persons with
limited mechanical aptitude or experience. The apparatus is
adaptable to a wide variety of ladder designs and can be modified
conveniently for special leveling situations.
It will be apparent that various modifications can be made in the
particular ladder leveling apparatus described above and shown in
the drawings within the scope of the present invention. The size,
configuration and arrangement of components can be different to
meet specific requirements. Also, additional channels, bolts and/or
plates can be included if desired. These and other changes can be
made in the ladder leveling apparatus provided the functioning and
operation thereof are not adversely affected. Therefore, the scope
of the present invention is to be limited only by the following
claims.
* * * * *